"The Strategy of Conflict" changed the development of game theory in several ways, but none was more important than Schelling's focus on real life examples, situations or games that are relevant to what we encounter in our daily lives. Before Schelling, game theory analysis was abstract and mathematical; it focused on zero-sum games, where interests were purely conflicting and there were no incentives to cooperate. Game theorists built convincing abstract models for these types of games, but its application was limited, since most interactions were a mixture of conflict and mutual dependence. In other words, analysis focused on pure conflict, a limiting cases of real world interactions, while in "The Strategy of Conflict" Schelling attempts to generalize game theory analysis to richer games that are `played' in the real world. His generalization introduced the concepts, commitments, threats, promises, communication systems, focal points, and randomization of strategies into game theory (chapters 1~8), which was then used to analyze the its applications in national security (chapters 9 and 10).
If you are studying game theory, this book is a must read. If you are just interested in game theory, I'd recommend reading this book too.